The following abbreviations are herewith defined, at least some of which are referred to within the following description of the prior art and the present invention.
AWG Arrayed Waveguide Grating
CPRI Common Public Radio Interface
C-VID Customer-VLAN ID
EPON Ethernet PON: IEEE 802.3ah
FTTH Fiber to the Home
GEM GPON Encapsulation Method
GPON Gigabit-capable PON, ITU-T G.984 series
GbE Gigabit Ethernet
ID Identification
MM Multi mode (fiber)
NetOp/NO Network Operator
ODF Optical Distribution Frame
OLT Optical Line Terminal
OIM Optical Interface Module
PON Passive Optical Network
Rx Receiver
SFP Small Formfactor Pluggable Optical Module
SM Single Mode (fiber)
SP Service Provider
S-VID Service-VLAN ID
TDM Time Division Multiplexing
TRx Transceiver
Tx Transmitter
VLAN Virtual Local Area Network
WDM Wavelength Division Multiplexing
XPS Cross-point Switch
In the emerging WDM-PON fiber access technology, one of the areas currently attracting a lot of interest relates to enhancing the capability of physical layer unbundling. Physical layer unbundling refers to a network architecture where multiple service providers (SPs) share a common data-link layer to provide voice, video and data services to subscribers. For example, physical layer unbundling allows different service SPs to use the individual wavelengths of a WDM-PON (fiber access network) to provide voice, video and data services to subscribers. In this way, improved competition in fiber access networks would be achieved as described in Broadtrends article: “Unbundling GPON: Bitstream Makes Most Sense . . . For Now” Jul. 6, 2010 (the contents of which are incorporated by reference herein). It is understood that physical layer unbundling, or using the more common term “Open Access”, implies a network operator (NetOp, also called NO) being responsible for the operation of the physical network plant and potentially also the physical layer active equipment. The network operator may or may not be the owner of the physical network and may or may not be a SP.
The dominating technology today for fiber access is TDM-PON (EPON, GPON) where the subscriber access to multiple SPs is achieved by L2 open access technologies (see the Broadtrends article). FIG. 1 (PRIOR ART) is a block diagram illustrating the basic architecture of a GPON 100 utilizing an exemplary conventional L2 open access technology. In this N:1 VLAN scheme, each SP 102-1 . . . 120-N uses a S-VID 104-1 . . . 104-N to represent them in the Access and Aggregation network 106 and a corresponding C-VID 108-1 . . . 108-N to represent the end user service (voice, data, video). On the GPON's OLT 110, each end user (ONT 112-1 . . . 112-M in the FTTH case) is represented by a GEM-port 114-1 . . . 114-M. The SP's S-VID 104-1 . . . 104-N is mapped to the end user GEM-port 114-1 . . . 114-M for transport over a PON 115. At the ONT 112-1 . . . 112-M, the end user 116-1 . . . 116-M has access to the selected SP services. For simplicity, just one OLT 110 and one PON 115 from this OLT 110 has been shown. The problem with L2 open access technologies is that the traffic of different SPs 120-1 . . . 120-N need to come together and pass a common packet processing device (e.g., Ethernet switch or similar—located in OLT 110). This architecture where all SPs need to come together gives rise to trust issues in terms of security and fairness as well as some limitations when it comes to service differentiations within the OLT 110 or in an aggregation device upstream from the OLT 110.
Alternatively, TDM-PON can also provide subscriber access to multiple SPs using different L1 open access technologies. FIGS. 2A-2B (PRIOR ART) are block diagrams illustrating the basic architectures of two WDM-PONS 200a and 200b utilizing exemplary conventional L1 open access technologies. In FIG. 2A, the WDM-PON 200a shows the case when the NO is the owner of the active and passive PON equipment 201 (including ONTs 202-1 . . . 202-M, wavelength multiplexers/demultiplexers 204 and 206, an OEO 208 and an ODF 210) which connect SPs 212-1 . . . 212-N to end users 214-1 . . . 214-M. In this case, the NO has to use the ODF 210 and manually patch each SP interface to the OEO port (which translates the SP's optic which are wavelength un-specific to the specific PON wavelength representing an individual end user 214-1 . . . 214-M). If desired, the NO can also make use of an optical switch to replace the manual patching, albeit at a very high cost. In FIG. 2B, the WDM-PON 200b shows the case when the NO is the owner of the passive PON equipment 216 (including wavelength multiplexers/demultiplexers 218 and 220, and an ODF 222) but not the active PON equipment 224 (including ONTs 226-1 . . . 226-M) which connect SPs 228-1 . . . 228-N to end users 230-1 . . . 230-M. In this case, the SP-1 228-1 (for example) has to provide the correct wavelength to the ODF 222. This means that the SP 228-1 risks having unused expensive WDM-ports in case an end user 230-1 (for example) switches to another SP 212-N (for example) or in a case the take rate is slow or unsuccessful. Plus, the SPs 228-1 . . . 228-N need to have a substantial amount of GbE ports (if this is the line speed per wavelength) and corresponding patch cabling since each port represents one wavelength line (being in service or potentially coming onto service). In both WDM-PONs 200a and 200b it is evident that the number of optical patch cords (cabling) from each SP is substantial, which will increase even more with customer turn-over. Hence, there has been and still is a need enhance the capability of physical layer unbundling (Open Access). This need and other needs are satisfied by the present invention.